The effects of nutrition and exercise on preventing the development of coronary heart disease are very important, although the mechanism by which this prevention takes place is not known. In this proposed research, a detailed investigation of the possible mechanism of action of nutrition and exercise on steroid and lipid metabolism will be undertaken. The following specific areas will be studied: 1) Effect of nutrition and exercise on steroid excretion. 2) Effect of exercise on serum lipids and body fat. 3) Effect of steroids on serum lipids and body fat. The objective of this research program is to study specific mechanisms of action of nutrition and exercise on serum lipids and the possible role of steroid hormones in these mechanisms.